Opua fanworm find sparks experts’ vigilance call

11 Jul 2018

The discovery of Mediterranean fanworm at Opua has prompted renewed calls from biosecurity experts for boaties to be extra vigilant for unwanted marine pest hitchhikers.

Sophia Clark, Biosecurity Manager – Marine & Strategy for the Northland Regional Council, says officials were alerted recently following the initial discovery of a single fanworm (Sabella spallanzanii) by mooring contractors at Opua.

The fanworm was found growing on a mooring block in the inner Bay of Islands, opposite Opua Marina. In response, the council had deployed two teams of Northland-based diving contractors, who had recovered about a dozen more fanworm in three spots over a several hundred-square metre area.

Ms Clark says the fanworm probably came from an unidentified infected vessel that – based on the large size of some of the fanworm recovered – had potentially moored in the area some time ago. Both the marina and mooring owners in the area had been notified of the find.

"Divers will continue to search on a regular basis over the next couple of months and remove any fanworm they find, but so far searches of other moorings and vessels in the wider area have been fanworm free."

"At this point, we're hopeful the situation has been caught early enough that we can accurately determine the extent of any infestation and remove any fanworm from the area."

Ms Clark says timing is crucial when it comes to attempts to contain fanworm, which are unwanted because they can form dense beds, forcing out other species (including natives) and interfering with other species natural process like breeding.

"Eradication of fanworm in newly-infested areas is possible, but only if the population is caught early." "As an example, we're now only about a year away from being able to officially declare fanworm eradicated from Tutukaka Harbour following an incursion there several years ago."

She says officials are very grateful to the mooring contractors who detected the Opua fanworm and promptly reported it to council.

The council has reiterated its earlier messages to boaties that it's vital to ensure their vessel and any associated equipment is clean and free from fouling which may contain marine pests like fanworm.

"Under regional council rules, it's an offence to transport marine pests in Northland." "Vessels entering Northland and moving between harbours must have no more than 'light fouling' on their vessel." (Light fouling is classified as a slime layer and/or barnacles, and up to five percent macrofouling).

Ms Clark urges people encountering marine pests to notify the regional council as soon as possible by phoning (0800) 002 004 or emailing marinebiosecurity@nrc.govt.nz